The top mount is a standard frame pump peg. The bottom plate is a
kickstand plate rather than a pump mount. The non-drive chainstay
should have a ridge or spine upon which to mount the other end of the
pump. In your image it's hard to see if that's true, but I think so.

I think it's almost certainly designed for a Zefal HP or HPX. At the end
of the pump head, those pumps have two sort of flat plastic pieces with
a concave curve cut out to fit up against a frame tube.http://www.zefal.com/en/pumps/253-hpx-protection.html
They're about 19mm wide and 3mm thick.

One of those plastic bits is almost, but not quite, axial with the pump.
It looks to me like it would slip perfectly into that slot.

I think it's almost certainly designed for a Zefal HP or
HPX. At the end of the pump head, those pumps have two sort
of flat plastic pieces with a concave curve cut out to fit
up against a frame tube.http://www.zefal.com/en/pumps/253-hpx-protection.html
They're about 19mm wide and 3mm thick.

One of those plastic bits is almost, but not quite, axial
with the pump. It looks to me like it would slip perfectly
into that slot.

The Mt Zefal version is shorter and fatter with the same HPX
head.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

On Monday, December 3, 2018 at 6:20:57 PM UTC, wrote:
Old Supergo Access hardtail MTB made from Columbus Cromor, with a top peg brazed behind the seat tube. Gotta be Shrader. Top and bottom mounts look like this:

On 12/4/2018 5:19 PM, Andre Jute wrote:
On Monday, December 3, 2018 at 6:20:57 PM UTC, wrote:
Old Supergo Access hardtail MTB made from Columbus Cromor, with a top peg brazed behind the seat tube. Gotta be Shrader. Top and bottom mounts look like this:

On Wednesday, December 5, 2018 at 7:12:40 AM UTC-8, AMuzi wrote:
On 12/4/2018 5:19 PM, Andre Jute wrote:
On Monday, December 3, 2018 at 6:20:57 PM UTC, wrote:
Old Supergo Access hardtail MTB made from Columbus Cromor, with a top peg brazed behind the seat tube. Gotta be Shrader. Top and bottom mounts look like this: